What is a subduction zone

At subduction zones, two tectonic plates converge, and one is thrust beneath the other. These settings host profound geohazards. The largest earthquakes on Earth are generated on the contact between these two tectonic plates, and the resulting motion at the seafloor triggers large tsunamis. Chains of active volcanoes form along subduction zones, many of which are capable of explosive eruptions. These seismically and volcanically active settings create dynamic landscapes that can produce catastrophic landslides. Large population centers around the world are located along subduction zones and thus immediately exposed to the hazards they pose, including within the

United States. The Pacific Northwest experienced an earthquake on the scale of the 2011 Tōhoku earthquake 323 years ago and is capable of hosting future earthquakes of this size. The next major eruption of Mt. Rainier has the potential to devastate major urban centers in the state of Washington. Large landslides such as the 2014 event near Oso, Washington, are a common occurrence in the Pacific Northwest, Alaska, and Puerto Rico. Even more people are vulnerable to the far field effects of subduction zone hazards, as painfully illustrated by the tsunami produced by the 2004 M9.1 Sumatra earthquake. Despite the enormous social significance of these hazards to many, the basic physical and chemical processes controlling the occurrence and magnitude of these natural events remain poorly understood. The purpose of SZ4D it to provide transformative new insight into controls on the fundamental processes underlying these hazards.